MAINTAINERS: correct PCI git tree address

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

MAINTAINERS

@@ -5195,7 +5195,7 @@ PCI SUBSYSTEM
 M:	Bjorn Helgaas <bhelgaas@google.com>
 L:	linux-pci@vger.kernel.org
 Q:	http://patchwork.ozlabs.org/project/linux-pci/list/
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/linux.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git
 S:	Supported
 F:	Documentation/PCI/
 F:	drivers/pci/